Lift-enhancing vortex flows generated by plunging rectangular wings with small amplitude

D. E. Calderon, Z. Wang, I. Gursul

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Experiments in a water tunnel have been carried out on low-aspect-ratio rectangular wings undergoing a smallamplitude harmonic plunge motion at Reynolds numbers 10,000 and 20,000.Aseries of measurement techniques have been used, including force measurements, hot film, particle image velocimetry, and volumetric velocimetry measurements, to study the lift enhancement as a function of forcing frequency. Multiple peaks in the time-averaged lift have been observed, occurring at frequencies in the order of natural vortex-shedding frequencies of the stationary wings. It is postulated that interaction between the leading-edge and trailing-edge vortices contributes to the selection of the optimal frequencies for the time-averaged lift. At a specific Strouhal number, an adverse interaction between the vortices results in a vortex dipole that directs flow upstream. A comparison between a NACA 0012 and flat-plate profile provides further insight into the advantages and disadvantages of using a thinner profile in low-Reynoldsnumber flows.
Original languageEnglish
Pages (from-to)2953-2964
Number of pages12
JournalAIAA Journal
Volume51
Issue number12
DOIs
Publication statusPublished - Dec 2013

Fingerprint

Vortex flow
Velocity measurement
Strouhal number
Force measurement
Vortex shedding
Aspect ratio
Tunnels
Reynolds number
Water
Experiments

Cite this

Lift-enhancing vortex flows generated by plunging rectangular wings with small amplitude. / Calderon, D. E.; Wang, Z.; Gursul, I.

In: AIAA Journal, Vol. 51, No. 12, 12.2013, p. 2953-2964.

Research output: Contribution to journalArticle

@article{83adf0625aa742a28447e4256fb8b2c4,
title = "Lift-enhancing vortex flows generated by plunging rectangular wings with small amplitude",
abstract = "Experiments in a water tunnel have been carried out on low-aspect-ratio rectangular wings undergoing a smallamplitude harmonic plunge motion at Reynolds numbers 10,000 and 20,000.Aseries of measurement techniques have been used, including force measurements, hot film, particle image velocimetry, and volumetric velocimetry measurements, to study the lift enhancement as a function of forcing frequency. Multiple peaks in the time-averaged lift have been observed, occurring at frequencies in the order of natural vortex-shedding frequencies of the stationary wings. It is postulated that interaction between the leading-edge and trailing-edge vortices contributes to the selection of the optimal frequencies for the time-averaged lift. At a specific Strouhal number, an adverse interaction between the vortices results in a vortex dipole that directs flow upstream. A comparison between a NACA 0012 and flat-plate profile provides further insight into the advantages and disadvantages of using a thinner profile in low-Reynoldsnumber flows.",
author = "Calderon, {D. E.} and Z. Wang and I. Gursul",
year = "2013",
month = "12",
doi = "10.2514/1.J052600",
language = "English",
volume = "51",
pages = "2953--2964",
journal = "AIAA Journal",
issn = "0001-1452",
publisher = "American Institute of Aeronautics and Astronautics Inc.",
number = "12",

}

TY - JOUR

T1 - Lift-enhancing vortex flows generated by plunging rectangular wings with small amplitude

AU - Calderon, D. E.

AU - Wang, Z.

AU - Gursul, I.

PY - 2013/12

Y1 - 2013/12

N2 - Experiments in a water tunnel have been carried out on low-aspect-ratio rectangular wings undergoing a smallamplitude harmonic plunge motion at Reynolds numbers 10,000 and 20,000.Aseries of measurement techniques have been used, including force measurements, hot film, particle image velocimetry, and volumetric velocimetry measurements, to study the lift enhancement as a function of forcing frequency. Multiple peaks in the time-averaged lift have been observed, occurring at frequencies in the order of natural vortex-shedding frequencies of the stationary wings. It is postulated that interaction between the leading-edge and trailing-edge vortices contributes to the selection of the optimal frequencies for the time-averaged lift. At a specific Strouhal number, an adverse interaction between the vortices results in a vortex dipole that directs flow upstream. A comparison between a NACA 0012 and flat-plate profile provides further insight into the advantages and disadvantages of using a thinner profile in low-Reynoldsnumber flows.

AB - Experiments in a water tunnel have been carried out on low-aspect-ratio rectangular wings undergoing a smallamplitude harmonic plunge motion at Reynolds numbers 10,000 and 20,000.Aseries of measurement techniques have been used, including force measurements, hot film, particle image velocimetry, and volumetric velocimetry measurements, to study the lift enhancement as a function of forcing frequency. Multiple peaks in the time-averaged lift have been observed, occurring at frequencies in the order of natural vortex-shedding frequencies of the stationary wings. It is postulated that interaction between the leading-edge and trailing-edge vortices contributes to the selection of the optimal frequencies for the time-averaged lift. At a specific Strouhal number, an adverse interaction between the vortices results in a vortex dipole that directs flow upstream. A comparison between a NACA 0012 and flat-plate profile provides further insight into the advantages and disadvantages of using a thinner profile in low-Reynoldsnumber flows.

UR - http://www.scopus.com/inward/record.url?scp=84891070554&partnerID=8YFLogxK

UR - http://dx.doi.org/10.2514/1.J052600

U2 - 10.2514/1.J052600

DO - 10.2514/1.J052600

M3 - Article

VL - 51

SP - 2953

EP - 2964

JO - AIAA Journal

JF - AIAA Journal

SN - 0001-1452

IS - 12

ER -